Not sure what you mean by Reaper Transport items. The transport buttons such as Play, Stop and Pause?
Seems more like a REAPER question than a Playtime question. For triggering the transport actions, you can just add MIDI shortcuts in REAPER's action window. But you don't get visual feedback. Playtime doesn't add any visual feedback support for REAPER transport. It supports visual feedback for Playtime slots and scenes only.